In general, a clutch is a mechanism for alternately establishing and disestablishing a coupling relationship, wherein, when actuated, an input for supplying mechanical energy is coupled to an output wherein mechanical energy is delivered. Clutches are known in a variety of designs for a variety of applications. Among these are various kinds of friction clutches such as multiple plate clutches, centrifugal clutches, cone clutches, or basket clutches, non-slip clutches such as “dog” clutches, hydraulic clutches that employ a viscous fluid as a coupling medium, electromagnetic clutches, wrap spring clutches and belt clutches.
Various belt-type clutches are known. For example, the patent to Hupp, U.S. Pat. No. 2,576,605, discloses and claims a combination, including a “V-belt disposed to clutch a drive sheave for power transmission and wherein the belt is loose on the sheave when declutched therefrom, a pair of guides for the belt to control the clutching action of the belt when the belt is tightened upon the sheave, each guide being disposed to engage the outer surface of a flight of the belt adjacent the sheave, and a single support for said guides disposed to provide freedom of floating action therefor under the influence of said belt and to maintain said guides in spaced relation correlated to the spacing of the belt flights in final clutch tightened position to effect a tensioning of the belt.” However, the clutch described in Hupp is designed for power transmission. The clutch has a continuous V-belt, arranged to transfer power between a driven rotating shaft and a rotatable shaft and is not suitable for controllably engaging through a fractional turn and/or a small number of turns,
As a further example, the patent to Love, U.S. Pat. No. 701,489 discloses and claims a belt wrench, having “a handle portion, the forward end of said handle portion being curved upward to form the contact point or nose . . . , an opening formed through the handle portion at the forward part thereof, a strip of flexible material secured to the underside of the handle portion at a point in the rear of the opening, a bolt passing upward through the flexible strip and through the handle portion and having a nut threaded upon its upper end for the purpose of securing the strip to the handle, said strip passing from its point of securement upward through the opening around the object to be gripped and back again through the opening . . . ” However, while belt wrenches can perform a frictional gripping function via the belt, the frictional grip is not varied under the control of an actuator to give a controllable frictional grip.
Despite the evident capabilities of conventional belt clutches and belt gripping tools such as belt wrenches, there remains a need for a clutching device that is capable of controllably engaging through angles ranging from a fractional turn through a small number of turns.